Downpour
by from russia with love47
Summary: It started with a box. It ended with something much bigger. A serial killer under the assumed identity of Roy Montgomery is out in the open, hell bent on torturing the one person who always seems to escape death, Kate Beckett. Unthinkable danger is on the horizon. A storm is coming, and they might not be able to control the outcome this time. Post Watershed. T for violence.
1. Chapter 1

**Set after season 5, maybe sometime in July so Alexis and Martha will be around a lot. I know I really suck at updating stuff, but I'm going to try and have Lost wrapped up by the end of the summer. Thanks for reading, reviews are appreciated, especially corrections/constructive criticism, it's very helpful! The T rating is for violence/language.**

**Disclaimer: I do not own Castle or any characters created by AWM, only the story.**

* * *

_"I can't give you anything but love!"_ he sang with the wooden spoon as his microphone. The smooth jazz filtered through the loft creating a light, happy feeling. Alexis and Martha sat at the bar, Martha with a sizeable glass of wine, each watching the antics of Rick and his fiancee.

"Rick, stop! Stop it, you're dripping pasta sauce everywhere!" she giggled. Kate Beckett, soon-to-be Castle, actually giggled. Their smiles widened as he continued to sing, and drip. He tossed the spoon into the pot, grabbing her by the waist, they spun around the kitchen. Him singing, her laughing; it was a picturesque evening at home. The instruments played them out, the song finished on the final note from the saxophone. They ended with her in a dip, him staring lovingly down at her. Alexis took a picture on her phone before either of them noticed.

"Pasta's burning." Kate said. Rick helped her back up, and returned to stirring the sauce while she strained the noodles. They had just served the pasta when the doorbell buzzed.

"I'll get it." Rick said, hustling over to the door. He swung it open to reveal a delivery boy.

"Evening, Mr. Castle. If you could just sign here."

"Thanks a lot." he said closing the door, package in hand.

"Darling, did you order something?" Martha asked.

"No, I assumed one of you did." They each shook their heads. "Kate, it's addressed to you."

"That's weird." he handed her the package. She took the card from the top.

_To: Kate  
Best regards: Roy Montgomery_

"What the hell?" Anger, unconceivable anger was what she felt.

"Kate, what's wrong?" she pushed the card toward him.

"What kind of fucked up joke is this?" she asked.

"Who would do something like that?" Rick asked in turn.

"Dad, what's wrong?" Alexis's question went unanswered. With one swift slash of the knife, the tape was separated. Carefully, she pushed aside the top. Her stomach gave a nauseated lurch.

"Castle, call Esposito." her voice was oddly calm.

"Why? What's in there?"

"Just tell him to get over here and to bring a team." He pulled out his phone and hit Esposito's speed dial. Ending the call, Castle peered inside the box. The surprise he got was a gag that had him bent over catching his breath. Within the hour the place was swarming with cops. CSU, Lanie, Ryan, Esposito, Gates, and a handful of uniforms were hunched over staring at the contents of the box.

"You've gotta be one sick bastard to do something like this," Was Esposito's immediate response. Beckett stood nearby, biting at her fingernails.

A few uniforms had to be taken outside, some of them lost their lunches in the sink. A well preserved arm, from the elbow down, the color of mocha lay inside. No nerve endings sticking out, neat cuts, bone cleanly sawed; it appeared to be the work of someone that knew what they were doing.

"Lanie?"

"Yeah, sweetie?"

"Do you think it's _his_?" her friend looked at her with sympathy, sadness, and a hint of rage.

"I'll have to run some tests, but if I had to guess..." Beckett nodded. "I am so sorry sweetie." The box was taken, along with its contents, and after statements were collected, the loft gradually began to empty. Ryan and Esposito said their goodbyes, only Gates lingered.

"Detective, I understand that you've been through quite an ordeal tonight. Try and get some sleep, take tomorrow off if you need it."

"Thank you, sir, but I don't think I can sleep until I catch the son of a bitch that did this." Gates smiled and offered a knowing look.

"I didn't think so either. First thing tomorrow I will gather a team and send them to the cemetery. Just to make absolutely sure. I assume I'll see you then." she made her exit, leaving Beckett and Castle alone in the hall. Kate turned and buried her face in Rick's chest, inhaling his cologne. He wrapped his strong arms around her petite frame, and kissed her hair. Neither slept much that night.

* * *

"Okay, pull her up!" the lead worker called. The guy manning the machine slowly pulled the mahogany coffin back into the light. It was loaded into the hearse, and sent to the Coroner's. It was _his_ funeral in reverse, exempt from the music, and troops of officers, paying their respects to a man that gave everything, his life included, to protect them. A twig snapped under someone's foot and Beckett flinched, feeling the burn of the bullet through her chest. The scar emitted a sharp ache, deep into the cavities of her chest she felt it.

Back at the Medical Examiner's office where _his _body was to be exhumed. The lid was cracked open to reveal an empty coffin. Except at the bottom. Someone had carved a message. A message for her.

_This is just the beginning._


	2. Chapter 2

"This is just the beginning." Ryan said aloud for the hundredth time, throwing his baseball to Beckett.

"Saying it over and over isn't going to make it go away, Ryan." Beckett snapped at him, catching it.

"I'm just trying to figure out what it means, Boss."

"We know what it means. It means that some lunatic wants me dead."

"You don't know that." Castle chimed in.

"The hell I don't, that jackass dug up Montgomery just to play mind games with me."

"Maybe that's all it is. A mind game, no substance to it."

"That's a nice fantasy you got there bro, but in all my years of detective work, you do not dig up a dead body and send one of its arms to a cop just to say hello. This guy wants something." Esposito said ominously, snatching the ball out of the air, and tossing it to Castle, who as usual, dropped it. "Nice, bro. Real nice."

"Do we even know the arm belongs to Montgomery?" Castle asked.

"Dude, we've got an empty coffin, and something tells me that Montgomery didn't just walk outta that grave." the phone rang.

"Beckett. Yeah, okay. Mmhm, thanks Lanie. I will, you too. Bye." they stared at her expectantly. "DNA confirms it. That's Montgomery's arm."

"Detective Beckett?" the group turned away from the murder board, and faced Gates. "A word?" Beckett followed obediently into the office and shut the door. Gates closed the blinds, fully aware of the boys attempting to listen in.

* * *

"I've seen a lot of weird shit go down in all my years at IA, but this, I have to say, takes the proverbial cake." Gates held out a gold flask.

"I agree, sir." Beckett commented, unscrewing the cap, and taking a swig of the bitter liquid.

"Like I said when I first came, I'm not looking to dishonor your Captain's name, I knew Roy Montgomery, and he was a great cop. Truly one of New York's Finest, but I think it's time you told me the whole truth." Beckett's eyebrows shot up.

"I'm not sure what you mean, sir."

"Oh, bullshit. We both know that Roy was involved in something illegal back in the day." Gates stated, satisfied with Beckett's lack of protest. "Now, you have my word. This will not leak back to IA." Beckett sighed, and leaned forward. Grabbing the flask off of the desk, she took another large gulp.

"Where should I begin?"

* * *

Over two hours later, Beckett walked out of Gates's office, feeling lighter than she had all week.

"Yo, Beckett! What was that about?"

"Yeah, you were in there a long time."

"She knows."

"About?" the boys chorused.

"Montgomery."

"What do you mean?" Ryan asked, disbelieving.

"I mean she knows everything." Neither said a word, but rather took her by the arm and pulled her into the conference room. Esposito locked the door and Ryan shut the blinds.

"What the hell were you thinking? Exposing Montgomery like that," Espo shook his head in disgust.

"I really didn't have a choice.

"There's always a choice, Beckett." She was surprised to see Ryan looking so angry.

"She already suspected most of what I told her."

"Oh, yeah? And what happens when she goes and brings this back to IA?"

"She promised she wouldn't. Gates is our captain, you need to start trusting her a bit more."

"Roy Montgomery is our captain, or have you forgotten?" Esposito spit back, her eyes darkened with rage.

"MONTGOMERY IS DEAD!" she could hear every pair of footsteps freeze, every voice silenced. "Or have you forgotten?" With that, she left the room, slamming the door shut behind her. She was aware of the unshed tears that stung her eyes, aware of all the cops watching her, and in that moment she thought, _where's Castle? _Beckett grabbed her jacket and headed for the stairs, knowing the ancient elevator would take too long.

* * *

"Kate?" Lanie asked, peeling off her blue latex gloves. Kate let out a heart-wrenching sob. "Oh, honey. I know, it's alright, you're okay, shhh." she said, stroking the woman's light brown hair. Though she was much taller, Kate buried her face in Lanie's neck and cried. "You want to talk about it?" she murmured softly as the tearful hiccups died down.

"It's stupid." she replied, sniffling. "I'm sorry, I shouldn't've bothered you."

"Why don't you come into my office, I'll make you some coffee."

A few minutes later, they were settled in Lanie's office, each with a cup of coffee.

"I guess it just hit me, that he was really gone. Then, I fought with the boys, and I really just needed to get out of there, away from all the testosterone in the room."

"I didn't think it bothered you." Lanie said, taken aback.

"I don't know, it's hard being a woman in a field like this. I don't feel like I can let them see me as less than a cop."

"And you're using the badge as a shield?" Beckett shrugged. "Sweetie, you know the boys love you, but I understand where you're coming from, I feel the same down here. I mean, I'm kept company by dead people, and Perlmutter."

"Hard to tell which is worse." Beckett chuckled.

"Definitely Perlmutter." They laughed together, and Beckett drained the rest of cup.

"Well, I guess I should be getting back."

"Alright, next time you scare me like that, I'mma smack you." Lanie called after her.

* * *

When she returned to the bullpen, she was welcomed by an awkward silence, and the boys' icy stares. She approached them.

"I'm sorry. I should have checked with you guys first before talking to Gates."

"We're sorry too, we shouldn't have chewed you out like that. This is probably more hard on you than it is on any of us."

"So, can we just call a truce, and forget this happened?"

"Sure." she offered them a small smile, and patted them each on the shoulder.

"Oh, and do you know where Castle went?"

"Actually, I haven't seen him in hours."

"I don't even remember him leaving."

"Yeah, he went to the Little Boys room and never came back..." they all exchanged a meaningful look before getting up and racing towards the men's room.

* * *

Beckett, the first to reach the door shouldered it open.

"Jesus!" she immediately shifted her gaze, the boys showed up, flanking her closely.

"Sorry LT." he zipped his fly and shook his head.

"Castle? You in here?" Beckett drew her gun and pushed open each stall door, stopping at the handicapped stall. She took a deep breath, and nudged the door wide open. She dropped her gun, and fell back, her vision darkening. Something caught her before her head hit the tile.

"Oh my God, Javi. Look." It was written in scarlet across the sterile, white tiles of the wall.

YOU'VE BEEN WARNED


	3. Chapter 3

**For the purpose of this story, the Medical Examiner's Office is just going to be what would be the basement area of the precinct. I have no idea where it actually is in the show, as they never give a specific location, but this way is much easier and quicker to get the story going. Thanks to all that have left reviews!**

* * *

"Lanie, I need a blood type test done stat."

"Why? Do you think it's Montgomery's?"

"Please, just do it." Lanie gave her an odd look before taking a swab of the bloody message on the wall.

"I'll be right back, I'm gonna bring this down to the lab."

"Alright, thank you." Beckett moved closer to the wall, studying it as if their guy would just reveal himself.

"Are you okay, Boss?"

"Yeah, you're taking this remarkably well."

"Castle is resourceful, as long as we find him quickly he'll be all right." she didn't sound so sure.

"Guys, take a look at this." They moved closer to examine what she indicated. "See this pattern here? It looks like it was drawn on with someone's finger."

"You think we can lift prints?"

"We can try." After collecting their print samples, they headed downstairs to see Lanie about the lab results.

* * *

"Hey Lanie."

"Hey sweetie, how ya doing?"

"Yeah, I'm fine." she lied.

"Mmhm, keep holding all that in, you're gonna get an ulcer." she said for about the hundredth time.

"Thanks. What do we got?"

"Well the blood type is O negative and Montgomery was AB Positive. What's wrong?" Her gaze shifted over to Beckett's downcast face.

"Castle is O negative."

"Girl, why didn't you tell me he was missing?"

"I wanted to confirm that the blood is his first."

"You are taking this eerily well."

"I just want him to come home safe."

* * *

"Alexis? Martha? Could you come down here a minute?"

"One second, darling!" Alexis came bounding down the stairs.

"Hey Kate, you're home early. Where's dad?"

"Alright, what is it?" Martha asked, joining them.

"I think you should sit down." Each took a seat next to each other on the couch, Kate occupied the chair across.

"What is it, darling? Where's Richard?"

"Yesterday a fragment of Roy Montgomery's arm was sent here,"

"Oh, how awful!" Martha exclaimed.

"This morning, his coffin was exhumed and brought into the Coroner's. The body was missing and there was a message carved in the bottom for me."

"What did it say?" Alexis, ever the inquisitor.

"_This is just the beginning."_

"Are you alright?"

"Yes." she lied. Alexis's eyebrows shot up. "No. Anyway, I met with Gates and went over some details, then I went to see Lanie. When I got back to the bullpen an hour later, I realized that I hadn't seen your dad in a while. I asked the boys and they said he went to the bathroom and hadn't come back." Alexis's cobalt eyes widened with terror. "There was another message for me in one of the stalls."

"What did this one say?" Martha asked.

"_You've been warned. _It was written in blood. The blood we found was a type match to Castle's." Alexis let out a loud cry, and clapped a hand over her mouth. Shaking, she began to cry.

"Oh, darling. Shh, it's alright. He'll be just fine, this is your father we're discussing."

"I will do everything I can to bring him back." Kate said, blinking away tears.

"We know you will. How are you holding up, sweetheart?"

"I'll be fine once I find Rick. If you're okay here, I need to get back."

"Of course, I'll be fine. I know you'll find each other. You always do." Kate nodded, and exited the building. Sliding into her cruiser, she rested her head on the wheel and released a tired sigh.

* * *

Upon entering the precinct, she saw Lanie about to step into the elevator. She jogged forward and stepped in beside her friend.

"Kate, I was just about to call you. I got results from the fingerprint samples you brought me."

"Great," they stepped off at the homicide floor and pulled Ryan and Esposito into the conference room. Lanie opened her briefcase, she pulled out the samples and a picture of their suspect.

"The prints were a match to Ryan Otis, 24, unemployed." The picture was of a sandy haired guy with green eyes and youthful features.

"That's the guy that delivered the package."

"Are you sure?"

"Of course I'm sure, only he was dressed as a delivery boy. If he's unemployed maybe someone hired him to bring the package up and then grab Castle."

"Why wouldn't they just send the package through the mail?"

"When I got the package, I could smell decomposing flesh. Maybe they didn't want to alert any of the carriers? Anyway, they could have left a money trail we can follow. Ryan check into Otis's financials, see if there are any irregularities; sudden deposits, large withdrawals, anything like that."

"You got it, Boss."

"Thanks Lanie."

"Anytime, I'm gonna check for prints in the coffin." Beckett nodded and advanced to the murder board. She pinned Otis's picture under suspects, near Montgomery's and Castle's under missing persons.

"Beckett, I found a deposit of 20,000 in Otis's account."

"Great, can you trace it?" Ryan began furiously typing, and clicking.

"It traces back to an account in Newark under the name Aaron Worth."

"Run the name. Esposito, do you have an address for Ryan Otis?"

"221B, the Bronx."

"I'm gonna assemble a team, Ryan let me know if you find anything on Worth."

"Why a team?"

"It's 7:30 at night. I really don't want a repeat of last time."

* * *

"Ryan Otis, open up, it's NYPD, we have a warrant!" Beckett pulled a few strings with Judge Markway. In her impatience, she took a step back, and swung her leg forward, effectively breaking down the door.

"Clear!"

"Clear!" This was called until every room had been cleared.

"Dammit!"

"Don't worry Beckett, we're gonna get this guy."

"I think I just did..." she pointed out the window to where a guy had just jumped from the bottom of the fire escape. "Move, move, move!" Half the team went down the fire escape and the others flew through the front of the building. Beckett and Ryan were the first to reach the alley he disappeared down.

_Pop, pop, pop!_

__"Dispatch, this is One Lincoln Forty, we have shots fired." she repeated the address into the walkie, still running, she dodged the debris of the alley and they bullets that came whizzing past her. Somewhere back she lost Ryan. The alley dead ended. Very slowly, she turned and looked up to see him perched on a balcony. He smiled sweetly as he aimed the gun.

_Pop, pop, pop, pop._


	4. Chapter 4

The first shot was fired by his gun. The bullet grazed her shoulder, and she felt warm blood seeping through her now wrinkled white shirt. The second and third fired by her, one to his leg, and the other to the hand holding the gun. The fourth was his last desperate attempt to kill her as he fell. He slammed onto the trashcans, and only the pained groans coming from his direction let her know that he wasn't dead. _Yet. _ A small voice whispered in the back of her head.

An hour later she was seated in the back of an ambulance, talking to Ryan and Esposito; her arm wrapped in gauze. With two gunshot wounds and three cracked ribs, Ryan Otis had been patched up and was currently seated in the back of a cruiser.

"That was some nice shooting, Beckett. Bro, you should've seen her. She took one right to the shoulder and just kept shooting, it was awesome!" Ryan filled Esposito in on the details, animatedly gesturing with his hands.

"You know, instead of watching, you could've tried to help me with the bad guy on the balcony."

"Naw, you had it." Ryan grinned.

"Always." she faltered at her automatic response, she sucked in a sharp, pained breath. "Umm, why don't we take him back to the precinct, get some answers?"

"We'll get him back, Beckett." Esposito said, placing a hand on her uninjured shoulder. They each gave her a small, hopeful smile.

"Why don't you head home, we can interrogate Otis in the morning." Ryan tried, though he knew that she wasn't going to stop. A small part of him wanted her to decline, because even though he wanted her to be able to relax, he knew that every second they argued about it was a second closer to not finding Castle.

"Hell no, Kev. That son of a bitch is going to pay." Ryan's grin returned.

* * *

"Detective Ryan!" Ryan looked up to see two familiar redheads walking towards him.

"Mrs. R, Alexis, what are you guys doing here?"

"We came to see Katherine. We wanted to know how the investigation is going."

"She just headed to Observation to talk to Esposito, she should be heading into Interrogation any minute."

"So, you have him? The guy that took my dad?"

"Not exactly. We believe that this guy is working for someone who wants something with Beckett. We think they're using Castle to get to her."

"Can I watch? From Observation, I mean."

"Uh, is it okay for her to-"

"She's more mature than all of us, Detective. Don't worry about her."

"That's what I thought." he turned and motioned for them to follow. The door to the Ob. room swung open, and Beckett came out, face turned to the floor. They watched as she paused, took a deep breath, and entered Interrogation 1. Ryan gave a silent greeting to Esposito, who stood up to allow Martha to take his chair, while Alexis occupied front and center where Castle usually sat.

"Good evening Mr. Otis, I'm Detective Kate Beckett, but you already know that, don't you?"

"Lady, I got no clue what you're talking about."

"Cut the crap, Otis." she paused, and stared directly into his eyes. "Where is he?" she asked calmly.

"Where's who?"

"Where is he?" her voice took on a dangerously silky tone.

"Like I said, I don't have any idea what you're talking about."

"Then why did you shoot at me in that alley, Mr. Otis? Who hired you?"

"I thought you was some gangbanger trying to pop me."

"Surely, you saw the whole swat team that was on your tail."

"In my neighborhood, you see a cop, you run for it. I didn't do nothin' wrong."

"Who hired you?" she asked again.

"I wasn't hired, I don't know what you mean."

"A few days ago, four installments of 20,000 dollars were transferred into you bank account. You want to tell me where those came from?"

"Sure, I got a job with the postal service."

"You must think I'm an idiot. What kind of postal service pays it's workers 80 grand the first week on the job."

"I dunno, this kind?" he smirked.

"You've got quite a rap sheet." She opened the leather folder, and pulled out his file. "Domestic violence charges pressed against you by your now ex-wife, Beth. Assault of an officer not that much later, robbery and assault with a deadly weapon. Add all that to the 5 oz. of heroin we found in your apartment and you're looking at 15 years in the slammer. Now, tell me Mr. Otis, do you really want to spend 15 years in prison because of some jackass that has you on his payroll?" he remained silent. "I can talk to the DA, get you a deal. You could get off with only 5 years max. I suggest you take it." she stared him down, not letting her frustration take over just yet. If it came to that, she'd just have to scare him a bit more. "Now, I'm going to ask you one more time. Where is Castle, and who wants me dead?"

He laughed, a cold laugh that echoed around the room. Back in Observation, Ryan and Esposito were waiting for her to snap.

"Go to hell, bitch." And snap she did. They'd only seen Beckett lose control once like this before, and that was when Alexis was in trouble. That was nothing compared to this. She kicked the bottom of his chair as she had done previously, this time much harder. His back slammed to the ground, and he let out an agonized whimper. But she wasn't done with him.

"Who has Castle? Where is he?" she yelled. His silence lasted to long for Beckett's patience, her gun was aimed directly at his forehead. "Right now, you think this is a game, but trust me, you do not want to play with me. With my connections, you will be dead, and your identity will be wiped clean. No one will ever know you existed, or that I killed you. Or better yet, I will keep you around for a while, and you will see just how serious I am. You have exactly 10 seconds before I pull this trigger, do I make myself clear?" he continued to stare at her, and at 5 she brought her foot down on his left arm. His scream filled the room, loud enough to where the entire precinct could hear. No one interfered though because they knew that Beckett would get him back, no matter what it took.

"3...2..."

"OKAY, OKAY!" He sobbed. "Dude goes by the name of Moriarty."

"Moriarty? Like the villain from the Sherlock Holmes books?" her tone was disbelieving.

"Yeah, yeah. That's the one."

"Where can I find him?"

"I don't know." she cocked the gun. "I swear to God, I don't know. He gave me a cellphone that I can reach him by. It's under a loose floorboard in my bedroom. That's all I know!"

"Good," she holstered the gun. "I appreciate the information, Ryan. But keep in mind that if any of this information turns out to be false, I won't rest until you give me the absolute truth."

* * *

"Yo, Beckett, are you okay?" Esposito asked as she entered the Ob. room.

"Yeah, I'm-. Alexis, Martha?" she paused upon seeing them. "I'm sorry you had to see that." Alexis pulled her in to a tight hug.

"He deserved it."

"Detective Beckett?" Alexis released her, and Kate turned to see Gates in the doorway. "LT took Otis to booking. I'm not surprised he talked so easily."

"Sir, you heard?"

"I think everyone did, but nobody has to know that. In fact, I saw nor heard anything. Did you Esposito?"

"No, sir." Espo smirked.

"Ryan?"

"No, sir."

"Mrs. Rogers, Alexis?" they shook their heads.

"Good, and to be honest, I think he'll keep his mouth shut for fear of losing his life."

"The gun wasn't loaded anyway."

"Girl, you pulled a Fallon on his ass!"

"He was a douche, but the guy knew how to interrogate. Why don't we all go home and get some rest, we can follow up on the lead tomorrow. I think I'll pay a visit to Aaron Worth as well." They walked out to find a nearly empty precinct.

"I heard you busted that guy's ass Beckett." Karpowski said, approvingly.

"Man, she curb stomped him. You should've seen it."

"I wish I could've. Night, guys."

"See ya, Karpowski."

* * *

"How are you guys holding up?" Kate said, handing them each a glass of wine.

"Kate, you do know I'm only 19, right?"

"We're home now, I'm not a cop. I already put my shield in the safe." she chuckled. Alexis shrugged and took a big sip.

"Agh," she spluttered, spitting a bit of wine back in the glass. "That's disgusting!"

"It's an acquired taste, Lex." she laughed, taking a sip of her own wine. Alexis glared daggers at her.

"I'm gonna go turn on a movie, join me when you're feeling a bit more mature." Alexis pushed Kate playfully, and strode over to the couch.

"She's lucky to have you for a future step-mother."

"I'm not trying to be her mother, just a friend."

"And that is where you differ from Gina about the whole marriage thing. In the end, that's what will truly make you a good mother to her."

* * *

**So, I figured I'd be nice and hold off from a big cliffhanger like the previous chapters. If you like that kind of thing, don't worry they'll be back :P. Anywho, I hope you liked it, especially Kate's little adventure into the dark side, that was fun to write. Well, I'm tired, and midnight is always the best time to upload chapters so, see ya next chapter, and don't forget to leave a review and tell me what you think so far.**


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